1. Field of the Invention:
The present invention relates to an element for supporting suspension-springs such as those of railway wagons and the like.
More particularly, the supporting element is of the type having a bottom plate for the connecting of the supporting element to a railway wagon, a supporting plate extending parallel to the bottom plate, a positioning collar perpendicularly extending from the supporting plate on the opposite side of the bottom plate, an intermediate plate interposed in parallel between the bottom plate and the supporting plate, a first ring of elastomeric material coaxially disposed with respect to the positioning collar and interposed between the bottom and the intermediate and a second ring of elastomeric material coaxially disposed with respect to the positioning collar and interposed between the intermediate plate and the supporting plate, to which it is connected by the contacting surfaces.
2. Background of the Related Art
As known, railway wagons are essentially composed of two or more wheel assemblies above which a box structure is disposed in which passengers or goods to be transported are housed.
Generally, the box is to be elastically suspended with respect to the wheel assemblies, known as trucks, through interposition between the box and the trucks of a plurality of vertically disposed metallic, helicoidal springs.
These springs are subjected to deformations in an anomalous way during the execution of curves by the wagon, particularly when they are disposed on lateral sides of the wagon. In fact, during this time the trucks each rotate about a vertical axis with respect to the box and the box inclines laterally with respect to the trucks due to centrifugal force. The springs are therefore obliged to follow the relative movements between the corresponding trucks and the box while bending along their longitudinal axis.
To confine the anomalous deformations to which the springs are subjected, it is known that each of them is engaged with the truck and with th box by interposition of suitable supporting elements which are elastically deformable.
A first type of known supporting element comprises, essentially, a bottom plate which is connected to the truck or to the wagon box, a supporting plate, parallel to the bottom plate, on which acts one end of the spring and a rubber elastic ring interposed between the bottom plate and the supporting plate and which is rigidly connected to the same by a rubber-metal union.
From the supporting plate extends, from a central position and towards the direction opposite to the bottom plate, a positioning collar intended to be inserted at the end of the spring in order to inhibit shifting of the latter with respect to the supporting plate.
During the execution of curves by the wagon, the rubber ring is elastically deformed both due to tangential forces and to the couples transmitted by the spring to the supporting element; thus the spring tends to deform in the above specified manner.
The rubber ring's deformations corresponding to the supporting elements respectively associated with the opposed ends of each spring make the supporting plate of the same elements tend, within certain limits, to be oriented so as to reciprocally align the axes of the relevant positioning tangs. In this way the anomalous deformations of the spring are considerably reduced.
In spite of the above, the supporting elements of this type present a satisfactory behavior only when they are associated with springs positioned near the longitudinal axis of the wagon, and therefore subjected to deformations which are relatively confined during the execution of the curves. Conversely, these supporting elements have been found not to be able to sufficiently reduce the anomalous deformations of the springs when they are positioned near the extreme lateral sides of the wagon.
In order to remedy these limitations, supporting elements have been made, conceptually similar to those of the type previously described, but provided with two elastic rings having the same dimensions and rigidity, axially separated by an intermediate plate extending parallel to the above mentioned plates in a median position between the same. The elastic rings are interposed one between the bottom and the intermediate plate and the other between the intermediate and the supporting plate, and are rigidly connected to the same by a rubber-metal union.
The presence of two elastic rings instead of one confers on these supporting elements a greater functionality in comparison with those of the type previously described. Nevertheless, the supporting elements provided with two elastic rings are not capable of sufficiently reducing the anomalous deformations of the springs.
This is due to the fact that the design constraints of the suspensions of which the springs in question are part do not permit one to make the elastic rings with a material having a smaller rigidity than that of predetermined values. At such values, in fact, the deformations of the rings, due to compression and shear stress, would negatively affect the whole behavior of the suspension.